Attachment of a first component to a second component for any of a variety of applications may be made by any of several known methods of fastening, including mechanical or chemical fastening. Mechanical fastening, while often practical and reliable, is not always usable for every application. For example, where a first component is being attached to a second component and it is not desirable or practical to drill into or otherwise modify the second component for mechanical attachment, chemical fastening is the only other alternative. This is the case where, for example, a component is to be attached to a glass surface, the second component. An example of a component-to-glass arrangement may be seen in the automotive industry where a rear view mirror or a metal hinge needs to be attached to a glass surface. Other examples of component-to-glass attachment needs exist such as in home and office construction.
The early challenges faced by those attempting to attach a component to glass using chemical fastening included early partial or complete failure brought about due to heating-cooling cycles and ultraviolet radiation.
While modern day adhesives have generally overcome the failure of the adhesive to hold the component in place over time, problems still remain in terms of difficulty and speed of application, time for setting, and cost. Typical adhesive materials known today are not easy to apply (usually to the component) and the application process takes some time. Once applied to the product, typical setting times are lengthy and are inconsistent with the high speed demands of the modern moving assembly line. Finally, and not inconsequentially, today's component-to-glass assembly and bonding processes using adhesives are expensive due to high material and high logistics costs as well as material waste caused by inefficient and outdated application techniques.
Current component-to-glass adhesive compositions offer concrete advancements in the state of the art, although known compositions suffer from one or more of the drawbacks described above. For example, in U.S. Pat. No. 5,710,215, a method and material mixture for the manufacture of reactive hotmelts is disclosed. That reference teaches the method of mixing a meltable hydroxyl functional or amino functional polymer mix with a powdered or solid surface deactivated poly-isocyanate (or a suspension of such poly-isocyanates) in a low volatility carrier fluid. Other publications (WO9325599 and EP 0922720) propose similar powder adhesives, but require the use of one or more deactivating agents to deactivate the isocyanate.
While providing an advancement in the art of adhesive polyurethane powder, the use of either a deactivating agent or a deactivated isocyanate in such a composition presents a number of disadvantages, including extending bonding time and extending curing time while increasing material cost and, hence, production cost.
As in so many areas of fastener technology, there is room in the art of adhesives for attaching components to glass for an alternative method adhesive composition.